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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

A Parametric Study of Economical Energy Usage in Freeze Tunnels

Harrison, Marc A. 01 July 1980 (has links) (PDF)
An investigation into economical energy usage in freeze tunnels was conducted. Freeze tunnels are commonly used in the food processing industry to freeze products, and in some cases may use large amounts of electricity. An actual freeze tunnel was observed and modeled on a computer. A parameter study was conducted. The results of the parameter study indicated the efficiency and energy costs in freeze tunnels may vary widely. Important parameters included the Nusselt number, air temperature, and the ratio of fan work divided by the useful refrigeration effect. Although no single set of optimum conditions were found, methods for improving the effectiveness of freeze tunnels, both in existing and future designs, were discussed. It was also concluded that the ratio of fan work to the freeze tunnel's useful refrigeration effect was a dominant factor in the energy cost of operating a freeze tunnel.
122

Numerical modeling of the cooking extrusion of a bio-polymer

Wagner, Lori Luxenburg January 1987 (has links)
Cooking extrusion is becoming an essential processing step in a number of food processes. Modeling of extruder performance is the first step towards the ultimate goal of prediction of product properties and quality based on governing extruder characteristics and operation. The purpose of this study was to develop a numerical model of the cooking extrusion process. This involved. many facets of investigation. A 50% added moisture soy flour dough was selected as the material of study. The material properties for this 50% added moisture dough were then determined. The viscosity of this material was found to be both shear and temperature dependent in addition to exhibiting a yield stress. Both thermal conductivity and heat capacity were determined to be constant over the temperature range of investigation. Finally, although it was discovered that a reaction associated with cooking was present in the system, it was determined that it did not occur under the extrusion processes tested which were to be modelled and hence would not have to be accounted for in the model. These material properties were then incorporated in the three-dimensional finite element program, FIDAP, to model the flow of the l 50% added moisture soy flour dough through an extruder and die assembly. These numerical simulations yielded limited results. Only one case out of the multiple conditions which were attempted converged to a viable solution. As more success was found with a two-dimensional model, it is suggested that the problems of convergence could be due to mesh size and discretization of the three dimensional model as well as the difficult power law index of the material. Suggestions as to methods to overcome these problems are included. / Ph. D.
123

Institutional effects on grain producer price-risk management behavior a comparative study across the United States and South Africa /

Woolverton, Andrea Elizabeth, January 2007 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on December 18, 2007) Vita. Includes bibliographical references.
124

The comparison of productivity growth in the U.S. and Mexican food processing sectors

Alpay, Ebru 11 November 1998 (has links)
In this study, the rates of technological change in food processing sectors of U.S. and Mexico are compared through econometric estimation of both the unrestricted (long-run) and restricted (short-run) profit functions with first order autocorrelation correction. Then, the dual rate of productivity growth is computed and decomposed into its sources. The impact of environmental regulations on productivity growth is also analyzed through incorporation of a pollution abatement variable into empirical models. The hypothesis testing results on the existence of short-run equilibrium in capital markets indicated that the restricted profit function framework is the valid specification for the underlying production technologies of U.S. and Mexican food sectors during the sample period, and hence, our conclusions are based on restricted profit function models. Our results suggest that, in U.S., the average annual dual rate of technological change dropped from 0.76% during 1963-73 to 0.67% during 1974-88, increased to 0.72% between 1988-1990, and declined to 0.65% during 1990-93. In Mexico, the dual rate of technological change was sharply declining during most of the years of sample period, and the average annual rate dropped from 1.30% during 1971-74 to 0.01% between 1989-93. The dual rate of technological change was lower in U.S. than in Mexico during 1971-81 period, but the difference (dual technological change gap) was sharply declining. Starting from 1982, the dual rate of technological change became greater in U.S. than in Mexico and the difference was continuously increasing. Moreover, the decomposition of dual productivity growth into its sources reveals that technological change was the main source of productivity growth in both countries, although in Mexico, the effects of changes in output price on productivity growth outweighed the contributions of technological change during several years between 1982-94. The impact of capacity utilization had a minor impact on productivity growth in both countries. The estimated elasticities of input demand and output supply indicated that labor demand is price inelastic, while material demand and output supply are price elastic in both countries. The own price elasticity of material and output was higher in Mexico than in U.S. In both countries, input demands are affected most significantly by output prices, while output supply is most significantly affected by its own price. The estimates for elasticity of substitution between labor and material imply that labor and material are complement of each other in both countries, with the degree of substitution between them is higher in Mexico than in U.S. Finally, the estimated parameters corresponding to pollution abatement variable suggested that pollution abatement costs had no significant impact on the U.S. dual rate of technological change, and in turn, productivity growth rate, and this appears to be consistent with the fact that the share of pollution abatement costs is quite small in U.S. food processing sector. For the Mexico, the estimated parameters were individually significant, implying that one unit increase in pollution abatement variable reduced the dual rate of technological change by around 0.11% points during 1982-94 period. / Graduation date: 1999
125

Competitiveness of the B.C. food and beverage industry in the Pacific Rim: an empirical analysis of the influencing factors

Cain, Laura Lea-Anne 05 1900 (has links)
Factors or characteristics which influence the export competitiveness of British Columbia's food and beverage processing industries in the Pacific Rim markets (i.e., Japan, Hong Kong, Taiwan, China: Mainland, Singapore and South Korea) are studied using pooled time-series and cross-sectional data, for the years 1988 through 1992. Changes in exports and in export market share are explained by changes in systematic exogenous and endogenous differences amongst B.C. and competing provincial industries over the five year period. The results indicate that, converse to what is suggested in the literature, there is no statistical consistency in the explanatory capability of comparative cost, industrial organization, or firm strategy variables to explain competitiveness in Pacific Rim markets. Rather, it appears export success is due to many unique factors at the firm or provincial level. Hence, it is not possible to make generalizations about the competitiveness determinants of these industries in the Pacific Rim markets.
126

Competitiveness of the B.C. food and beverage industry in the Pacific Rim: an empirical analysis of the influencing factors

Cain, Laura Lea-Anne 05 1900 (has links)
Factors or characteristics which influence the export competitiveness of British Columbia's food and beverage processing industries in the Pacific Rim markets (i.e., Japan, Hong Kong, Taiwan, China: Mainland, Singapore and South Korea) are studied using pooled time-series and cross-sectional data, for the years 1988 through 1992. Changes in exports and in export market share are explained by changes in systematic exogenous and endogenous differences amongst B.C. and competing provincial industries over the five year period. The results indicate that, converse to what is suggested in the literature, there is no statistical consistency in the explanatory capability of comparative cost, industrial organization, or firm strategy variables to explain competitiveness in Pacific Rim markets. Rather, it appears export success is due to many unique factors at the firm or provincial level. Hence, it is not possible to make generalizations about the competitiveness determinants of these industries in the Pacific Rim markets. / Land and Food Systems, Faculty of / Graduate
127

Hazard analysis critical control point (HACCP) in a red meat abattoir

Wagude, Bethsheba Emily Akinyi 11 October 2007 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MSc (Food Science))--University of Pretoria, 1999. / Food Science / MSc / unrestricted
128

Pyrrhic progress : antibiotics and western food production (1949-2013)

Kirchhelle, Claas January 2015 (has links)
This dissertation addresses the history of antibiotic use in British and US food production between 1950 and 2013. Introduced to agriculture in the 1950s, antibiotics underpinned the 20th-century revolution in Western food production. However, from the late 1950s onwards, controversies over antibiotic resistance, residues and animal welfare began to tarnish antibiotics' image. By mapping both the enthusiasm and the controversies surrounding antibiotic use, this dissertation shows how distinct civic epistemologies of risk influenced consumers', producers' and officials' attitudes towards antibiotics. These differing risk perceptions did not emerge by chance: in Britain, popular animal welfare concerns fused with new scenarios of antibiotic resistance and drove reform. Following 1969, Britain pioneered antibiotic resistance regulation by banning certain feed antibiotics. However, subsequent reforms were only partially implemented, and total antibiotic consumption failed to sink. Meanwhile, scandals and public pressure forced the American FDA to install the first comprehensive monitoring program for antibiotic residues. However, differing public priorities and industrial opposition meant that the FDA failed to convince Congress of resistance-inspired bans. The transatlantic regulatory gap has since widened: following the BSE crisis, the EU phased out growth-promoting antibiotic feeds in 2006. The US proclaimed only a voluntary and partial ban of antibiotic feeds in December 2013. In the face of contemporary warnings about failing antibiotics, the dissertation shows how one group of substances acquired different meanings for different communities. It also reveals that the dilemma of antibiotic regulation is hardly new. Despite knowing about antibiotic allergies and resistance since the 1940s, no country has managed to solve the dilemma of preserving antibiotics' economic benefits whilst containing their medical risks. Historically, effective antibiotic regulation emerged only when differing perceptions of antibiotics were broken down either by sustained regulatory reform or large crises.
129

Food certification audits : a case study in the Western Cape

Valentine, Lucrecia Zinobia January 2008 (has links)
Thesis (MTech (Engineering))--Cape Peninsula University of Technology, 2008 / While there is a standard for quality and environmental auditors, there is no local or international standard for food safety auditing, which means auditors from different certification bodies can use their own discretion when auditing food establishments. There is a requirement to investigate the quality of work performed by South African food safety auditors. in order to establish whether they do in fact add value when conducting registration and certification audits. This is also an indication of the importance of improving and maintaining a high standard of food safety in the food services industry. The overall concept of food safety in South Africa IS clearly not defined. understood by only a few consumers, and not widely accepted. Research has shown that food retailers in South Africa in general do not believe food safety auditors are competent. In the wake of the Sudan Red scare two years ago. a long awaited food safety initiative was launched in February 2006. The scare pertaining to a carcinogenic food dye. which found its way into spices on local supermarket shelves, mobilized food industry role players to improve food safety standards. Under the auspices of the Consumer Goods Council of South Africa (CGCSA), the body responsible for establishing best practices and implementation standards, Food Safety South Africa (FSSA) will enable an organization to determine the exact nature and extent of possible and actual problems along the food supply chain. The key objectives of this research study are to determine whether one food certification standard is needed in South Africa and to assess the value added by the food auditors to their clients. Social research will be conducted within the ambit of the dissertation, with case study serving as research method. Both quantitative and qualitative research paradigms will be used to gather data for the research survey in support of the research question. forming the crux of the dissertation which reads as follow: "How can food safety auditors increase value added to the audit process in food environments in South Africa?"
130

Trade Negotiations in Agriculture: A Comparative Study of the U.S. and the EC

Gordon, H. William (Harold William) 12 1900 (has links)
This study applies Destler's institutional counterweights to Putnam's two-level analysis, substituting Liberal Institutionalism and Realism for internationalism and isolationism, in a comparative case study of the roles played by the U.S. and the EC in multilateral trade negotiations in agriculture under the aegis of the General Agreement for Tariffs and Trade during the first half of the Uruguay Round. Using game theory as an analytical tool in the process, this present study demonstrates that a clear pattern emerges in which stages of cooperation and deadlock can be easily anticipated in games of Chicken and Prisoners' Dilemma in accordance with various but predictable levels of institutional influence.

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